Method of increasing the durability of glassware



Patented Feb. 17, 1942 METHOD OF INCREASING DURABILITY OF GLAS SWARE Walter K. Berthold; Rockville, Conn., assignor to Hartford-Empire Company, Hartford, Conn., a corporation of Delaware No Drawing. Original application March 17,

durability.

1939, Serial No. 262,415. Divided and this application March 27, 1939, Serial No. 264,479

3 Claims. (01. 4-9-79 desirable to employ a glass which melts at a relatively lowtemperature, and especially in the automatic manufacture of glassware at high speeds, good working and rapid setting qualities in the glass are also desirable.

It is well known in the art that inclusion of\ certain ingredients in the batch will tend to re-' Ihave discovered a novel method durability.

form and/or to cool the interior of the glass article to the desired extent. The steam is preferably removed by introducing a scavenging current of air into the article.

The method maybe carried out automatically or-manually by any suitable means but I prefer 55 that the same be performed by the use of mechanism for blowing and cooling the article disclosed-in my copending application Serial No. 262,415, filed March 17, 1939.

My novel method appears to be of substantial advantage in improving the durability of glasses 'of substantially all types commonly employed in the glass industry. It has been particularly tested-in connection with ordinary silica-sodalime bottle glasses such as are commonly employed in the automatic production of gin bottles. Heretofore considerable difliculty has been experienced by glass manufacturers in providing suitable glass containers for gin, because the gin vigorously attacks the walls of the containers and causes a white precipitate if kept in storage for substantial periods of time. This frequently renders the goods unsalable. Various methods of preparing containers for gin from ordinary glasses have been proposed. One of these meth- This duce the melting point, and that other ingredi- 2o ents tend to improve the workability of the glass. ods which has been employ in COmmeYcial D However it is equally well known that the batches duction involves the treatment of the bottles by which melt at relatively low temperatures and/or the deposit'therein of pellets of sulphur prior to are readily workable by modern methods fretheir introduction into the anealing lehr. quently do not result in glasses having sufficient method is disclosed in U. S. patent to Urban E. durability. Hence it has been necessary to com- Bowes No. 2,046,302. This treatment of the bot- .promise in the selection of these ingredients and tles adds considerably to their cost, as it adds not frequently to sacrifice ease of melting and cheaponly the cost of the sulphur and the operation ness of manufacture to obtain a suflicient of depositing same in the bottles, but also re- 30 quires that the bottles be washed to remove the of treating bloom or deposit on the surface of the bottles glass, preferably during the stages of its manu-. resulting from this treatment. facture, by which a glass having desirable quali- In my novel e n wh Steam is blown ties with respect to its melting and workability, into and scavenged f o t b tt s, 0 d .but which otherwise would be insufficiently dur- 1:5 tional operations are required, nor is there subable for its intended purpose, may be improved stantial added expense if the steam is employed as to durability to an extent which will render for the purpose of expanding and/or cooling the it satisfactory. The principal object of this in- I bottles during their formation. vention is; therefore, to provide such a novel In the preferred manner of employing my method of treating glassware to improve this 40 novel method in the manufacture of glass bottles, Y a suitable automatic feeder may supply charges In general, this method comprises introducing of glass (which glass is of such composition as to into the glass article steam under pressure and suitably reduce the melting and manufacturing to thereafter remove substantially all of the costs) to a bottle machine which may be of any steam from the article before the glass is placed 4 well-known kind, as for example, the Hartfordin the lehr, preferably before its temperature is Empire Companys I. S. machine, in which the reduced below its low annealing temperature bottles are formed into parisons in the usual way (usually about 800 F. in common glasses). The and transferred to final blow molds in which they steam may be employed to blow the glass to final are then blown to final form. Preferably the so final blowing is effected by the application of steam under pressure. The application of the steam may be continued for a suitable period after the expansion of the bottle is completed to aid in urther chilling the interior of the bottle, after which it may be discontinued. Relatively dry remove the steam therefrom. Suitable apparatus for the application of the steam and the scavengingair is disclosed in my beforementioned copending application, but the use of my novel method is not dependent upon the use of the particular apparatus there disclosed.

The several steps in my method may be carried on either while the glass is in the blow mold or may occur, at least in part, after the mold is opened and whilethe bottle is at a relatively elevated temperature prior to its being placed in the annealing apparatus.

While I am unable at this time to fully and accurately explain the chemical and/or physical effect upon the walls of the bottles, which results in the increased durability, the fact that the durability is substantially increased has been established by careful durability tests made upon bottles treated in accordance with my method. As far as is now known, it appears that the effect upon the bottle wall surface is of substantially a different kind from that resulting from the prior methods of increasing durability, such as the sulphur treatment above described, in which earlier method it appears that the sulphur removes the alkali from the surface layer of the glass, probably forming a sulphate which appears as a bloom or deposit and which is washed ofi by the washing operation, leaving the air is then blown into and out of the bottle to,

surface of the glass relatively free from alkali. By my novel method, no bloom or deposit is created, nor does the bottle appear to undergo any injurious chemical change.

Having described my invention, what I claim is:

1. The method of increasing chemical durability of an article of glassware, which comprises the steps of introducing steaminto said article and thereafter circulating a scavenging fluid through the article to remove steam and all residual moisture from the interior thereof.

2. The method of increasing the durability of an article of glassware which comprises the steps of introducing steam into said article and thereafter circulating a scavenging fluid through the article to remove steam and all residual moisture therefrom, all before the temperature of the ar-- ticle has been reduced substantially below 800 F.

3. The method of manufacturing hollow articles of glassware, having increased durability to chemical attack, which comprises introducing glass into the molds of a glass blowing machine, blowing the articles to final form by the application of steam under pressure, thereafter applying a current of relatively dry air to the interior of the articles to scavenge the steam and all residual moisture therefrom, and thereafter annealing the articles.

' WALTER K. BERTHOLD. 

